code: def upvp_to_xy(up, vp):
      xc = (9 * up) / ((6 * up) - (16 * vp) + 12)
      yc = (4 * vp) / ((6 * up) - (16 * vp) + 12)
      return (xc, yc)
  
file_path: vispy/examples/demo/gloo/galaxy/galaxy_specrend.py
imports: import math
label_desc: Use image node_id 1 for calling a global function with example usage: upvp_to_xy(up, vp) and returns: xc,  yc